If you’ve decided that no, you’re never, ever going to upgrade to Windows 10, the free Never10 app might be just what you’re looking for.

Steve Gibson, the author of the popular freeware Shields UP! anonymity app, has released Never10 for Windows 7 and Windows 8.1 PCs. The idea is simple: The Never10 software will hide in the background and block any attempts by Microsoft to upgrade your system to Windows 10.

The Windows 10 upgrade is free until July of this year, but many users remain wary of it. Gibson claims these holdouts are “happy with their current version of Windows and have no wish to upgrade to Windows 10.” Gibson also takes the time to sate some common objections to Windows 10's software-as-service orientation: "Windows 10 has become quite controversial due to Microsoft’s evolution of their Windows operating system platform into a service which, among other things, aggressively monitors and reports on its users activities."

ZDNet’s Ed Bott has published a short guide for blocking Windows 10 updates that involves editing the registry. Gibson’s utility provides more automated responses, in a similar manner as GWX Control Panel, noted in this PCWorld guide to blocking Windows 10 updates. None of the methods can be considered foolproof, although it’s unclear to what lengths Microsoft will go to force users to upgrade to Windows 10.

Gibson’s program takes advantage of a back door in the Windows Update software, where individual PCs can be configured to stop forced upgrades. The Windows Update version that opens this backdoor was released in July, 2015, so the first step Never10 takes is to confirm you have the correct update with the backdoor built-in. “If the system being configured has a version of Windows Update which is older than the required July 2015 release, this utility will notify its user and will offer to download and install the required update to Windows Update so that Windows can be configured not to upgrade itself to Windows 10,” he writes.

Never10 is not a Windows 10 blocker, per se. Rather, it offers a control to either block or disable Windows 10. So if you do decide to upgrade in the future, you’ll have that choice. Note that Microsoft’s one-year free upgrade period expires at the end of July, however, so the clock is ticking.

Why this matters: Microsoft originally began offering Windows 10 as a carrot, but has since begun wielding the stick. Last year, Microsoft indicated that it would switch Windows 10 to a “recommended” update that would be automatically downloaded. Since then, users have complained of tricks Microsoft has pulled to force those updates. We still think Windows 10 is worth the upgrade—but if you want to say no, you should have that right.